1. Technical Field
The present invention generally relates to control of a computer chassis. More particularly, the present invention relates to handling of system management information in a computer chassis by a dual domain controller acting simultaneously as a satellite management controller and a baseboard management controller.
2. Discussion of the Related Art
Computer management demands are becoming more detailed as the computers themselves become more complex. Currently, computer management architecture is not very intelligent in how the central processing unit (CPU) manages the resources of the computer. Sensors, field-replaceable units, and circuit boards each have a different way of communicating whether or not it is operating within normal and expected parameters. The CPU monitors these devices by continuously polling each device to determine if there is a problem that needs to be reported, or if a device has been added or removed.
The monitoring performed by the CPU keeps the CPU from performing its primary tasks, such as running the operating system and application software. These monitoring requirements greatly impact the CPU performance as the system grows in size and complexity. Also, the monitoring is performed in a proprietary fashion on most existing computers. In addition, computer purchasers desire to have computers that monitor, analyze, and repair themselves.
In response to the problems of decreased CPU performance and the need for 100% computer availability, multiple computer vendors developed the Intelligent Platform Management Interface (IPMI). In addition, the computer vendors use Inter-Integrated Circuit (I2C) as a hardware-level communication layer between different integrated circuit devices within a system to connect the devices with the CPU.
IPMI is an open standard hardware management interface specification that defines how unique devices can all communicate with the CPU. With IPMI, the CPU makes requests and receives information from an IPMI event log through a baseboard management controller (BMC). The devices communicate in a standard way with the IPMI event log and the CPU only asks what has changed in the event log since the last inquiry.
The intelligence of managing the hardware has moved into the IPMI firmware layer. The CPU software layer now communicates in a standard way to the IPMI firmware. The system scalability is increased because the management intelligence is closer to the managed devices.
The IPMI standard includes the following elements: the Intelligent Platform Management Interface, the Intelligent Platform Management Bus (IPMB), the Intelligent Chassis Management Bus (ICMB), the Baseboard Management Controller (BMC), and the Satellite Management Controller (SMC).
The IPMI standard provides a specification for the controller command sets, including command sets for sensors, event logs, and sensor data record access along with the specification for the data formats. The data forms utilized by IPMI include sensor data records, event log entries, and field replaceable unit (FRU) inventory entries.
The IPMB is the I2C based, multi-master bus used for intra-chassis communication between the BMC and “satellite” management controllers (SMC). SMCs are management controllers that are distributed on other modules within the system, away from the “central” BMC. The ICMB is a bus used for chassis-to-chassis communication. The BMC manages the interface between the system management software and the platform management hardware, provides autonomous monitoring, event logging, and recovery control, and serves as a gateway between system management software and the IPMB and ICMB.
In a computer chassis, system management security is an issue if a central BMC is connected to SMCs that reside on computer board sets (CBS). Because there is one central BMC and one central event log, each CBS has access to system information about the other CBSs. Ideally, each CBS should have access to system information about itself without this information being visible to other CBSs, while also providing external system management information to the central BMC.
Compact Peripheral Component Interface, also known as CompactPCI® (specification 2.0, revision 3.0, PCI Industrial Computer Manufacturers Group, published Oct. 1, 1999), IPMI CBSs may be designed for a specific slot type (system, peripheral, or busless) or may be designed to operate in any slot type. Typically, the IPMI controller operates as either a BMC when installed in a system slot or as an SMC when in a peripheral or busless slot. However, the controller may be utilized only in one mode at a time; it cannot operate simultaneously as both a BMC and a SMC. Again, system management security is an issue because the CBS internal system management information is visible to other CBSs.
Accordingly, a need exists for a controller to operate as a BMC and SMC simultaneously in order to separate system management access into multiple domains for greater system management security.